1. Field of the Invention
The present invention relates to an LED circuit driving LEDs by commercial AC voltage.
2. Description of the Related Art
A light emitting diode (LED) is a semiconductor device configured as a p-n junction structure and emitting light by the recombination of electrons and holes. The light emitting diode may be manufactured to have a small size while having an excellent monochromatic peak wavelength and light emission efficiency and may be manufactured in an environmentally-friendly manner while having reduced power consumption, or the like. For these reasons, the light emitting diode is rapidly replacing existing lighting devices.
In general, the light emitting diode is driven by a DC power supply of several volts. Therefore, a circuit for driving the existing light emitting diode mainly uses a scheme in which commercial alternating current (AC) voltage is rectified and then constant current is supplied to a light emitting device using a converter such as a flyback converter.
The driving circuits have a relatively complex control structure and require several elements, such as abridge circuit, and a control integrated circuit (IC). In particular, a smoothing electrolytic capacitor has a short lifespan, such that the lifespan of the lighting device using the light emitting diode may be shortened. Further, the driving circuits directly using AC voltage may have light emitting diodes that are not driven at all times among light emitting diodes of a light emitting unit, which may determine the lifespan of the entire light emitting unit.